"Well, there's no point in trying to look like her, is there?" Helena Bonham Carter says, as she twiddles her monstrous fake £1m diamond ring. "And if you do try, you're just going to be perpetually disappointed."

"On no," Dominic West says. "Pointless. The thing we had going for us is, we're playing them when they're not in their prime. And we're younger than they were at the time."

Bonham Carter and West are playing the ultimate celebrity couple, Elizabeth Taylor and Richard Burton, in a new BBC4 film. It wasn't simply their level of celebrity that made them special; it was the scale of their lives. Both actors dealt only in superlatives raised to the power of X. So Taylor became the world's biggest child star when she made National Velvet at 12, and went on to become the world's biggest adult star. She was often called the world's most beautiful woman. She wore the world's most expensive rings, swaddled herself in the most extravagant furs, knocked back more drink than any of her contemporaries, popped more pills, married more (eight times to seven husbands), threw more tantrums, raised more money for Aids. And so the mythologising goes on. As for Burton, one of 13 children from a Welsh mining village, he became the world's biggest stage actor, the owner of the world's most seductive basso profundo voice. ("The theatrical equivalent of a big cock," he says dismissively in the film. "It doesn't mean you're actually a good lover.") He was one of the world's great drinkers, Shakespeareans, scrappers (see drink) and self-loathers. He could also wear a mean mink.

'She couldn't have been more womanly and he couldn't have been more manly. That was the great combination'

But what stood out more than anything was the epic nature of their love: it was intense, sexual, violent, competitive, obsessive. The couple met on the set of Cleopatra in 1963, when both were married to other people. It caused an outrage when they outed themselves as a couple on the Via Veneto in Rome during filming. The Vatican condemned their affair as "erotic vagrancy", an "insult to the nobility of the hearth". Even Taylor and Burton referred to it as "le scandale".

They married twice, divorced twice – and many of their friends believe they weren't quite done when, while happily married to his fourth wife, Sally, Burton died at the age of 58.

Burton And Taylor, the new biopic, does not indulge the melodrama. Instead, it is an intimate and poignant chamber piece set less than a year before his death. The pair had not seen each other for five years, and both were with new partners, when Taylor called Burton and asked him to star opposite her in Noël Coward's Private Lives. The play echoed their own lives: a divorced couple who loved each other intensely come together again. Both were paid the then unbelievable sum of $1m, and the show was sold out before the run started, in Boston in 1983. Not only did the public want to see the two great actors and lovers reunited on stage; there was a voyeuristic element, too – it looked as if Burton and Taylor were acting out their private life in public. In the film, Taylor seems to have hatched this plot (she was also a producer on the show) as a way of winning Burton back.

Elizabeth Taylor and Richard Burton on the set of Cleopatra, 1962. Photograph: Globe Photos

It's not the first Burton and Taylor biopic: last year's Liz & Dick, starring Lindsay Lohan and Grant Bowler, was panned. Many people feel that it is a presumption even to try to play them. Already, a biographer of the couple has said that Bonham Carter is insufficiently beautiful and West insufficiently Welsh or charismatic.

Both are aware of this and say they don't care. "I wanted to play her because she's fun," Bonham Carter says. "She was fantastic fun to play. That's what I loved about her. She had a huge sense of humour." She looks at West. "And I wanted to work with him." Bonham Carter, 47, is best known for her surreal collaborations with her long-term partner, director Tim Burton, while West, 43, will for ever be associated with his role as Baltimore cop Jimmy McNulty in The Wire.The pair have just finished shooting and Bonham Carter is flipping between American and English accents. "The claws are still in," she says.

Another plus about the film for Bonham Carter was that, because it was made for the BBC, there was a quick turnaround, no mucking about. "We didn't have long to prep because there is no money in it. I mean, serious money. We shot it in about 18 days. I love that. On Harry Potter, you're waiting for a year between each take. You've forgotten what you've done." That sounds boring, I say. She pauses. "You get paid very well, so I like Harry Potter. But here you get momentum, you don't get bored."

'Tim felt he was married to Elizabeth. His revenge was to become Richard. He'd go deep and silent and pause a lot'

How did they prepare? "I went to an astrologer," Bonham Carter says. She looks at West and bursts out laughing. "He thinks I'm barking. Heeheehee!" Bonham Carter laughs louder and more giddily than almost anybody I've met. "I've got a really good friend called Darby Costello. If I can't make a decision, I go to Darby and… she won't tell me what to do, but she can distil characters. She knew Elizabeth." She stops to correct herself. "She'd not actually met her, but she'd distilled her. She said that Elizabeth was a big Pisces, and was often attracted to people who were broken – she needed to heal them. This was her take on Burton: when she got down, she always had the capacity to get up, whereas he was laden with guilt, and obsessed with death. She was so Pisces."

What does that mean? "A lot of water. She was so liquid, so sensual. Burton called her 'Ocean'. Truman Capote talked about her liquid eyes, the way she moved. It was also the drink. That was her element. She existed on a different plane."

West remains silent and wide-eyed as she talks, and she's still looking at him. "Look, he thinks I'm a nutter! I said to Darby, can you just see if we would have got on? And the first thing she said about me and her was that she would have felt very safe with me. She said there were five houses between us." Eh? "Basically, from the moment you're born, all your moons stop in certain houses."

Bonham Carter also got her graphologist aunt to analyse both actors' handwriting. "My aunt said he was more of an academic than an actor. He should have been an academic."

West: "I think that's cobblers."

Bonham Carter: "Oh, OK. Heeheeheehee!"

West: "I think he loved to give the impression he was an academic and, like Brando, was often very dismissive of acting, and I think there's a fair amount of nonsense. His writing wasn't particularly interesting – it was sub-Dylan Thomas. Although he read a lot and was an intellectual in some ways, he was such a visceral, emotional performer." At his most nihilistic, Burton would quote Lear at himself, contemptuously: "Unaccommodated man is no more but such a poor, bare, forked animal as thou art." He had a thing about playing princes, West says.

Bonham Carter: "He did have a chip; she didn't."

West: "She pretended to be less clever than him. Less of a reader, less literate."

Bonham Carter: "A lot of people say she was incredibly well read, but she was prepared to play dumb. She was devoted to him, did everything he needed for his ego to be OK. Her sense of self was stronger than his. He was more fragile." She talked to a shrink friend about all the medication Taylor took; the shrink friend said that, because she'd been taking painkillers since she was 12 (she fell off her horse making National Velvet), she must have had a very high tolerance of them.

'She was so liquid, so sensual. She existed on a different plane.'

It's funny, Bonham Carter says: so many people have an image of Taylor as fat and drunk, pill-addicted and a little bit batty, when she was an incredible survivor. "She had a solid sense of self and survived the level of fame extraordinarily. She could have been like Marilyn or Judy, but she wasn't. She could have been a victim. She did the drug thing, but she lasted till she was almost 80."

How did West prepare to play Burton?

Bonham Carter answers for him. "He didn't go to the astrologer!"

"Well, I'd been meaning to, but..." He smiles. "I read a lot. Then just listening to him, and that was basically it."

Bonham Carter: "You went to Wales."

West: "Oh yes, I went to his birthplace. The thing about Burton is, he's one of the most romantic actors ever, because his story is so romantic. You really get that when you go to where he grew up, in Pontrhydyfen, which is a beautiful place. It's very like Switzerland, where he spent much of his life."

Bonham Carter says that there was more to her research than the astrologer, graphologist and shrink. She read the biography Furious Love, by Sam Kashner and Nancy Schoenberger. At the end of the book, Schoenberger explains why she had wanted to write about the couple. "She said she went to UCLA and the students said to her: 'Oh, I didn't know Elizabeth Taylor was married to Tim Burton.' She was so horrified, she thought she had to reclaim the name Burton. It's been hijacked." She bursts out laughing, just as she did when she first read it, with the actual Tim Burton, father of her two children, sitting next to her. "Tim said: 'What's so funny? Haven't they just died?' And I was like, 'No, but read this!' Then, when we were doing it, he felt fucking hell, like he was married to Elizabeth Taylor."

What was that like for Burton? "Ask Tim. I drove him up the wall. When I talked really strange, he'd go, 'Oh Jesus.' He hates it. He's now worked out how to have revenge. He adopts the character I'm acting opposite. So he suddenly became Richard Burton. I've got it on tape." She takes out her iPhone, which has bunny ears. "He'd go very deep and silent. He'd pause a lot. I think he'd kill me if I showed you."

But she does nonetheless. And it is very funny. Burton sits looking into the distance, morose, miserable. Between long silences he says, in a slow, lugubrious Welsh accent, "What a dump!" and, "It's filled with death" and, "Take him to the mines!" He became convinced that Bonham Carter, in her guise as Taylor, would dump him. "Tim was saying, 'I see what's happening. I'm Eddie Fisher; she's about to leave me. You actors, you luvvies. Goodbye, I'm Eddie Fisher.' " Fisher was Taylor's fourth husband, and Burton's predecessor. "Then Tim decided he was Mike Todd, because he was getting on a plane." Todd was Taylor's third husband and Fisher's friend; he died when his private plane, Lucky Liz, crashed in New Mexico.

As for West, he says his wife Catherine and his four children just found annoying his attempts to master Burton's accent.

Who do they think would be harder to live with, Taylor or Burton?

West: "Oh, he'd definitely be very difficult."

Bonham Carter: "I'd be infuriating. I was late all the time." She stops, embarrassed. "Sorry, I must stop saying 'I'. It's spooky."

They might get recognised in the street, but their fame is not on the hysterical level of Taylor and Burton's. Has there ever been an equivalent couple, in terms of star power, beauty, success?

West: "We have pictures of everything – there would be no mystique. You couldn't have quite as much fun publicly as they did. Also, a lot of the traditions of Hollywood and of British theatre have gone. They don't make those epics that are based on actors, rather than the special effects."

Bonham Carter: "Thank you, darling... And that's another thing I liked about Elizabeth: she ate, she loved her food. There are so many fucking women nowadays who just don't eat. They pick at a bit of lettuce and say, 'Oh God, I feel guilty.' She was a proper woman, she was unapologetically proud of it. And that's why I think they were icons, because she couldn't have been more womanly and he couldn't have been more manly. That was the great combination."

Would West have fallen for Taylor in real life?

West: "Oh God, yeah. God, yeah!"

Bonham Carter: "Yeah!"

West: "Love and lust. But I'd have been terrified. There were very few men who could take her on, but Burton could and that's why there was such a spark in Cleopatra. Because he was a swaggering lothario, really, and hugely confident at that time. He seduced her and wasn't intimidated by her at all. Her mega-stardom must have put every man off. I would imagine it must be pretty lonely for a woman to be that famous and that sexy and in demand. Not many men's egos would have been able to deal with that."

Could he? "God, no. Oh no."

Bonham Carter: "You would have, wouldn't you?"

West: "No. No way. No."

Bonham Carter: "You would have," she says gently. "You would have got used to it."

They are still flirting and tiffing in character. How would she have coped with Richard Burton?

"I would have sent him to my mother, who's a therapist."

And would she have fallen for him?

"I would probably have had a massive crush. I would have definitely tried to… what's the word?"

West: "Have sex with him?"

Bonham Carter: "Yeah! Hahahahaha! Have his babies! And I'd have definitely tried to fix him."

In the film, Taylor asks Burton what fuels their relationship: passion, sex or trust? He says it's being able to trust your most abject self to the other. She says: "It was trust? I thought it was my tits."

What do Bonham Carter and West think is the most important element in a relationship?

About this article

Dominic West and Helena Bonham Carter: being Burton and Taylor

This article appeared on p16 of the Weekend section of the Guardian
on Friday 12 July 2013.
It was published on
the Guardian website
at 04.00 EDT on Saturday 13 July 2013.
It was last modified at 20.31 EDT on Wednesday 21 May 2014.
It was first published at 04.01 EDT on Saturday 13 July 2013.